Silicon is conventionally extracted by the carbothermic reduction process, which is energetically very inefficient, besides being harmful to the environment. The proposed Solid Oxide Membrane (SOM) process to manufacture Silicon and other metals is energy-efficient and environmentally friendly. The process and its set-up are similar to those of a conventional Solid Oxide Fuel Cell (SOFC). However, the operating temperature is much higher, and therefore, the Nickel-Zirconia cermet that is used for anode in conventional SOFCs cannot be used in this process. The present work reports the development of a suitable anode cermet coating for the purpose. Based on known physical properties of various materials and the requirements of the application, it was decided to pursue the development of an anode based on Molybdenum-Yttria Stabilized Zirconia (YSZ) cermet. Research was conducted to develop with a process to make a Molybdenum-Yttria Stabilized Zirconia cermet coating that would adhere well to the SOM substrate, which is made from YSZ and would have good electronic conductivity and porosity. The molybdenum oxide and Yttria Stabilized Zirconia mixtures were milled together and slip-cast into pellets. The variation of the cermet characteristics was studied with respect to various milling times and sintering/reduction temperatures. YSZ substrate tubes were dip-coated with slurries of made from milled mixtures of Molybdenum Oxide and Yttria Stabilized Zirconia with methanol. They were sintered and reduced in an atmosphere of Argon with five percent Hydrogen, with the intention of getting Molybdenum-Yttria Stabilized Zirconia cermet coatings. These produced flaky coatings that did not adhere to the substrate. Thus, the experiments with Molybdenum Oxide and Yttria Stabilized Zirconia mixtures demonstrated the difficulty in making the cermets by that technique. Cermet coatings were made using a slurry of Molybdenum metal and Yttria Stabilized Zirconia powder. Molybdenum powder was milled with Yttria Stabilized Zirconia and the resulting powders were made into sluITY with methanol and dip-coated onto the substrate tubes. It was seen in the cermet coatings produced that the electrical conductivity and porosity increased, whereas adherence to the substrate decreased with increasing Mo-content in the cermets. In order to make a cem1et coating that had good electrical conductivity and porosity as well as adherence to the YSZ substrate, a double-layered Molybdenum-YSZ cermet coating was made with a zirconia-rich lower layer and a molybdenum-rich upper layer. This coating had good electrical conductivity and porosity, as well as adherence. This double-layer coating was recommended as the cermet coating for use as the anode for the SOM cell.

L’objectif de cette thèse est de mettre en évidence le comportement à l’échelle microscopique des composés organiques au cours des procédés de traitement de mélanges complexes, en particulier les procédés membranaires. Pour cela des outils expérimentaux et de modélisation ont été mis au point. Les méthodes de caractérisation expérimentale des mélanges complexes et de l’état de surface des solides utilisés sont entre autres la construction d’isothermes d’adsorption et la mesure des tensions interfaciales par la méthode de la goutte posée. Le cas étudié ici est celui de la filtration de solutions modèles de tensioactifs par osmose inverse. Nous avons montré que le comportement des composés organiques (tensioactifs) influence la performance du procédé membranaire et les propriétés de membranes. L’outil de simulation du comportement des composés en phase liquide et à l’interface liquide-solide permettant une description à une échelle plus fine que celle atteignable expérimentalement est la DPD (Dissipative Particle Dynamics). Une première étape a permis de simuler l’agrégation des tensioactifs en solution et de retrouver les valeurs expérimentales des concentrations micellaires critiques et nombres d’agrégation de tensioactifs anioniques. L’étude de l’adsorption des tensioactifs sur une membrane d’osmose inverse a été initiée, avec pour objectif de mettre en évidence l’organisation des composés à l’échelle locale. L’apport des outils développés a été démontré et leur utilisation pourra être approfondie dans des travaux ultérieurs. / The aim of this work is a better understanding of the microscopic behavior of organic matters during the wastewater treatment of complex mixtures, especially during the membrane processes. Both experimental and simulation methods were developed in this work. Experimentally, adsorption isotherms were built to study the adsorption of organic matters on the membrane surface during the filtration. The sessile drop measurement allowed investigating the surface properties (interfacial tensions) of the membrane. After the filtration of surfactants by reverse osmosis (RO), we found that the surfactants played an important role in the performance and the surface properties of the RO membrane. The DPD (Dissipative Particle Dynamics) simulation method was used to model the behavior of anionic surfactants in solution and at the solid/liquid interface from a more detailed aspect than experiments. Firstly, the micellization of three anionic surfactants in aqueous solution was simulated and the model was validated by comparing the equilibrium properties (the critical micelle concentration and aggregation number) of micelle solutions obtained from simulation to the experimental values in literature. Then the model was extended to simulate the adsorption of surfactants on the RO membrane. The construction of a system with a membrane was initiated, and the study on the organizations of surfactants at the membrane surface opens a door to further active research.

La demande sociétale en protéines végétales a augmenté d’environ 50% durant la dernière décennie. Les nouvelles tendances alimentaires et l’intérêt pour leurs propriétés font de ces protéines une alternative intéressante dans de nombreux secteurs industriels à moyenne et haute valeur ajoutée. L'objet de cette thèse est de progresser dans l'étude d’un procédé simple et robuste permettant la mise au point d'une éco-filière de production de protéine. L’objectif est d’étudier l’extraction et le procédé de purification de la protéine, à partir des plantes sélectionnées, afin de garantir la conservation de ses propriétés technologiques moussantes, émulsifiantes et gélifiantes. / Social requirements for vegetal proteins increased almost by 50% in last decade. New food trends and their interesting functional properties make these proteins a preferential choice for industrial sectors of middle and high added-value. The aim of this PhD Thesis is to contribute to the analysis of a simple and robust process able to favour an eco-industry for protein production. The objective is to study the extraction and the purification of the protein, from selected green-plants, in order to guarantee techno-functional properties such as foaming, emulsifying and gelling powers

Una de las aplicaciones más importante de los procesos de filtración por membrana es en el área de tratamiento de agua por ultrafiltración, nanofiltración u ósmosis inversa. Entre los problemas más serios encontrados en estos procesos destaca la aparición de los fenómenos de ensuciamiento y envejecimiento de las membranas que limitan la eficacia de la operación tanto en la separación de los solutos, como en el flujo de permeado, afectando también el ciclo de vida de las membranas.Para reducir el coste de la producción y mejorar la robustez y eficacia de estos procesos es imprescindible disponer de modelos capaces de representar y predecir la eficiencia y el comportamiento de las membranas durante la operación. Una alternativa viable a los modelos teóricos, que presentan varias particularidades que dificultan su postulado, la constituyen los modelos basados en el análisis de los datos experimentales, entre cuales destaca el uso de las redes neuronales. Dos metodologías han sido evaluadas e investigadas, una constando en la caracterización de las interacciones entre las membranas y los compuestos orgánicos presentes en el agua de alimentación, y la segunda basada en el modelado de la dinámica de operación de las plantas de desalinización por ósmosis inversa.Relaciones cuantitativas estructura‐propiedad se han derivado usando redes neuronales de tipo back‐propagation, para establecer correlaciones entre los descriptores moleculares de 50 compuestos orgánicos de preocupación para la salud pública y su comportamiento frente a 5 membranas comerciales de ósmosis inversa, en términos de permeación, absorción y rechazo. Para reducir la dimensión del espacio de entrada, y para evitar el uso de la información redundante en el entrenamiento de los modelos, se han usado tres métodos para seleccionar el menor número de los descriptores moleculares relevantes entre un total de 45 que caracterizan cada molécula. Los modelos obtenidos se han validado utilizando un método basado en el balance de materia, aplicado no solo a los 50 compuestos utilizados para el desarrollo de los modelos, sino que también a un conjunto de 143 compuestos orgánicos nuevos. La calidad de los modelos obtenidos es prometedora para la extensión de la presente metodología para disponer de una herramienta comprensiva para entender, determinar y evaluar el comportamiento de los solutos orgánicos en el proceso de ósmosis inversa. Esto serviría también para el diseño de nuevas y más eficaces membranas que se usan en este tipo de procesos.En la segunda parte, se ha desarrollado una metodología para modelar la dinámica de los procesos de ósmosis inversa, usando redes neuronales de tipo backpropagation y Fuzzy ARTMAP y datos experimentales que proceden de una planta de desalinización de agua salobre Los modelos desarrollados son capaces de evaluar los efectos de los parámetros de proceso, la calidad del agua de alimentación y la aparición de los fenómenos de ensuciamiento sobre la dinámica de operación de las plantas de desalinización por osmosis inversa. Se ha demostrado que estos modelos se pueden usar para predecir el funcionamiento del proceso a corto tiempo, permitiendo de esta manera la identificación de posibles problemas de operación debidas a los fenómenos de ensuciamiento y envejecimiento de las membranas. Los resultados obtenidos son prometedores para el desarrollo de estrategias de optimización, monitorización y control de plantas de desalinización de agua salobre. Asimismo, pueden constituir la base del diseño de sistemas de supervisón capaces de predecir y advertir etapas de operación incorrecta del proceso por fallos en el mismo, y actuar en consecuencia para evitar estos inconvenientes. / One of the more serious problems encountered in reverse osmosis (RO) water treatment processes is the occurrence of membrane fouling, which limits both operation efficiency (separation performances, water permeate flux, salt rejection) and membrane life‐time. The development of general deterministic models for studying and predicting the development of fouling in full‐scale reverse osmosis plants is burden due to the complexity and temporal variability of feed composition, diurnal variations, inability to realistically quantify the real‐time variability of feed fouling propensity, lack of understanding of both membrane‐foulants interactions and of the interplay of various fouling mechanisms. A viable alternative to the theoretical approaches is constituted by models developed based on direct analysis of experimental data for predicting process operation performance. In this regard, the use of artificial neural networks (ANN) seems to be a reliable option. Two approaches were considered; one based on characterizing the organic compounds passage through RO membranes, and a second one based on modeling the dynamics of permeate flow and separation performances for a full‐scale RO desalination plant.Organic solute sorption, permeation and rejection by RO membranes from aqueous solutions were studied via artificial neural network based quantitative structure‐property relationships (QSPR) for a set of 50 organic compounds for polyamide and cellulose acetate membranes. The separation performance for the organic molecules was modeled based on available experimental data achieved by radioactivity measurements to determine the solute quantity in feed, permeate and sorbed by the membrane. Solute rejection was determined from a mass balance on the permeated solution volume. ANN based QSPR models were developed for the measured organic sorbed (M) and permeated (P) fractions with the most appropriate set of molecular descriptors and membrane properties selected using three different feature selection methods. Principal component analysis and self‐organizing maps pre‐screening of all 50 organic compounds defined by 45 considered chemical descriptors were used to identify the models applicability domain and chemical similarities between the organic molecules. The ANN‐based QSPRs were validated by means of a mass balance test applied not only to the 50 organic compounds used to develop the models, but also to a set of 143 new compounds. The quality of the QSPR/NN models developed suggests that there is merit in extending the present compound database and extending the present approach to develop a comprehensive tool for assessing organic solute behavior in RO water treatment processes. This would allow also the design and manufacture of new and more performing membranes used in such processes.The dynamics of permeate flow rate and salt passage for a RO brackish water desalination pilot plant were captured by ANN based models. The effects of operating parameters, feed water quality and fouling occurrence over the time evolution of the process performance were successfully modeled by a back‐propagation neural network. In an alternative approach, the prediction of process performance parameters based on previous values was achieved using a Fuzzy ARTMAP analysis. The neural network models built are able to capture changes in RO process performance and can successfully be used for interpolation, as well as for extrapolation prediction, fact that can allow reasonable short time forecasting of the process time evolution. It was shown that using real‐time measurements for various process and feed water quality variables, it is possible to build neural network models that allow better understanding of the onset of fouling. This is very encouraging for further development of optimization and control strategies. The present methodology can be the basis of development of soft sensors able to anticipate process upsets.

La problématique de l’élimination de l’excès d’ions fluorure présents dans les eaux de forage destinées à la consommation humaine peut être résolue en utilisant plusieurs méthodes. Dans cette thèse, les procédés testés sont : l’adsorption sur des particules d’os de seiche, l’adsorption sur des particules de calcite en présence d’acide acétique, la nanofiltration et l’échange d’ions. L’objectif est d’optimiser les différents procédés pour des solutions modèles en ions fluorure, puis de réaliser pour ces conditions optimales le traitement d’une eau de forage tunisienne. La concentration limite en ions fluorure imposée par la WHO est de 1.5 mg.L-1. Les essais d’adsorption en utilisant l’os de seiche, disponible en Tunisie, sont simples à mettre en œuvre et permettent des traitements à petite échelle avec des coûts très compétitifs en utilisant un matériau non toxique. La défluoration de l'eau souterraine avec l’os de seiche présente une concentration résiduaire en fluorure de 1,3 mg.L-1 (TR = 61,5%). Dans le cas de la précipitation des ions fluorures sous forme de fluorite suivi de microfiltration, l’addition d’acide acétique aux particules de calcite (CaCO3) favorise l’élimination des ions fluorure. La défluoration de l'eau souterraine montre que l’eau traitée présente une concentration résiduaire en fluorure de 1,24 mg.L-1 (TR = 53,7%). En utilisant une résine échangeuse d’ions Purolite A520E, la défluoration de l'eau souterraine montre que l’eau traitée présente une concentration résiduaire en fluorure de 1,2 mg.L-1 (TR = 54%). La nanofiltration permet de traiter des volumes importants d’eau et les taux de rétention des ions fluorure sont satisfaisants (88% et 57%) / The issue of the removal of excess fluoride ions present in well water for human consumption can be solved using several methods. In this PhD thesis, four processes have been tested: adsorption using cuttlefish bone particles, adsorption on calcite particles with acid acetic addition, nanofiltration and ion exchange. The aim is to optimize the different processes by using model solutions of fluoride ions, and to treat a Tunisian groundwater at these optimal conditions. The limiting concentration given by the WHO is 1,5 mg.L-1. The adsorption using cuttlefish bone, available in Tunisia, is simple to implement and provides treatment at small scale with very competitive costs by using a non-toxic material. Defluorination of groundwater shows that the water treated with cuttlefish bones has a residual fluoride concentration of 1.3 mg L-1 (TR = 61.5%). In the case of precipitation of fluoride ions in the form of fluorite followed by microfiltration, the addition of acetic acid to the particles of calcite (CaCO3) promotes the removal of fluoride. Defluorination groundwater shows that the treated water has a residual fluoride concentration of 1.24 mg L-1 (TR = 53.7 %). Using a ion exchange resin Purolite A520E, defluorination groundwater shows that water treated has a residual fluoride concentration of 1.2 mg L-1 (TR = 54%). Nanofiltration is particularly interesting as it allows the treatment of large volumes. The retention of fluoride ions are again satisfactory (88% and 57%)

La filtration membranaire est une technique séparative utilisée fréquemment comme procédé permettant de retenir et d'extraire les microorganismes présents dans un fluide. Le mécanisme de sélectivité classiquement admis dans ce procédé est l'exclusion par la taille. Cependant, nos travaux ont permis de mettre en évidence un transfert de microorganismes à travers la structure poreuse des membranes au cours d'opérations de filtration, alors que les dimensions des cellules vivantes en suspension sont supérieures au diamètre moyen des pores de la membrane, entrainant une diminution du taux de récolte des microorganismes et une contamination de la phase perméat. Les caractéristiques morphologiques et nanomécaniques des cellules bactériennes sélectionnées pour nos travaux ont été observées et les propriétés du matériau membranaire modèle ont été mesurées. Grâce à ces informations, le transfert des bactéries aux premiers instants d'une filtration frontale a pu être évalué et le rôle de différents paramètres opératoires appliqués (type de souche bactérienne, composition physico-chimique de fluide filtré, PTM) a pu être commenté. Ainsi, nos résultats ont permis de préciser les mécanismes de sélectivités appliqués aux bactéries à Gram positif et à Gram négatif qui différent du fait des caractéristiques structurales de la paroi bactérienne (épaisseur et élasticité de la couche de peptidoglycane). Enfin, l'évolution du transfert de cellules vers la phase perméat a également été suivie et la mise en place du dépôt bactérien colmatant à la surface de la membrane a été observée. Le rôle de ce dépôt structuré sur les variations de débit et de transfert a donc pu être mis en évidence pour les trois modèles bactériens sélectionnés. Nos résultats ont permis de définir des conditions critiques (physiques, chimiques et biologiques) pour lesquelles le transfert de cellules bactériennes par déformation est amplifié au cours d'une filtration membranaire frontale. / Membrane filtration is a separation technique commonly used as a method for removing and extracting microorganisms present in a fluid. The selectivity mechanism is size exclusion. However, our work has highlighted transfer of microorganisms through the porous membrane structure during filtration operations, even if the size of the living cell in suspension is greater than the average pore size of the membrane, resulting in lowering of the accumulation rate of the microorganisms and thus contamination of the permeate phase. Morphological and nanomechanical characterization of selected bacteria cells used for our work were performed and the properties of the model membrane were analyzed. With this information, the transfer of bacteria dunring the first moments of the dead-end filtration has been evaluated and the role of operating parameters (type of bacteria strains, physicochemical composition of filtered fluid, TMP) has been studied. Thus, our results have clarified the selectivity mechanisms applied to Gram-positive and Gram-negative bacteria strains because of different structural characteristics of the bacterial cell wall (thickness and elasticity of the peptidoglycan layer). Finally, evolution of cells transfer to the permeate phase has also been followed, and the bacterial deposit clogging the membrane was observed. The role of the structured deposit on the variations in flow and transfer has been demonstrated for the three selected bacterial models. Our results have defined critical conditions (physical, chemical and biological) where the transfer of bacterial cells is amplified by deformation during a frontal membrane filtration.

Abstract Industrial wastewaters are complex waters, which can contain a large variety of compounds such as heavy metals and salts as well as nutrients, e.g. nitrogen compounds and phosphorous. Prevention of wastewater formation is not always possible and therefore new more efficient water treatment techniques are needed. Legislation also supports the use of more efficient water treatment techniques, which can lead to better purification results and the recovery of valuable compounds from wastewaters. One technique, which has been of interest, is membrane technology. Membrane technology can separate heavy metals, salts and nutrients effectively, also at low concentrations, which is not always possible with conventional water treatment methods. The main disadvantage of membrane technologies is membrane fouling, which reduces the membrane permeate flux and separation efficiency. In this thesis membrane techniques were combined into hybrid processes to increase the efficiency of water treatment to reduce fouling and to widen the application areas of membrane technologies, as well as to increase the awareness of the benefits gained when using hybrid membrane processes in wastewater treatment. Three different hybrid membrane processes were applied. Catalytically active nanofiltration membranes were used to purify real mine wastewaters from harmful compounds, including sulphate. A catalytic layer reduced the membrane fouling tendency. Micellar-enhanced ultrafiltration was applied successfully to the separation of heavy metals from phosphorous-rich wastewater of a fertilizer company to achieve selective separation. In addition, reverse osmosis and membrane distillation were applied to the concentration of heavy metals, a metalloid and nitrogen compounds containing synthetic wastewater efficiently. High volume concentration factor was achieved with the RO-MD process. In this thesis high heavy metal, metalloid, and salt removal efficiencies were achieved with all hybrid membrane techniques. Hybrid membrane techniques were also categorized based on their properties. The study provides new knowledge on hybrid membrane techniques in the removal of inorganic compounds from industrial waters. / Tiivistelmä Teollisuuden jätevedet voivat sisältää kohonneita haitta-ainepitoisuuksia, kuten raskasmetalleja ja suoloja. Teollisuuden jätevedet voivat sisältää myös ravinteita, esimerkiksi typen yhdisteitä ja fosforia. Jätevesien syntymistä ei aina voida ennaltaehkäistä, ja siksi uusille entistä tehokkaammille vedenkäsittelymenetelmille on tarvetta. Lisäksi myös lainsäädäntö vaatii entistä tehokkaampaa vesien puhdistusta, mikä osaltaan edistää entistä tehokkaampien puhdistustekniikoiden kehitystä sekä erotettujen aineiden talteenottoa. Yksi aktiivisen tutkimuksen kohteena oleva vesienkäsittelyssä käytetty menetelmä on kalvoerotustekniikka. Kalvoerotustekniikoilla voidaan erottaa tehokkaasti raskasmetalli-ioneja, sulfaattia ja ravinteita, kuten typpiyhdisteitä teollisuuden jätevesistä myös alhaisissa pitoisuuksissa, missä yleisesti käytettävät menetelmät voivat olla tehottomia. Yksi kalvoerotusmenetelmien ongelma on kalvojen likaantuminen, mikä alentaa kalvojen erotustehokkuutta ja vähentää tuottavuutta. Tässä tutkimuksessa kalvojen likaantumistaipumista on vähennetty yhdistämällä kalvoerotustekniikoita muihin erotusmenetelmiin hybriditekniikoiksi. Tässä työssä on tutkittu kolmea eri hybridimenetelmää. Sinkkioksidilla pinnoitettuja nanosuodatuskalvoja tutkittiin ja verrattiin kaupallisiin nanosuodatuskalvoihin kaivosteollisuuden vesien puhdistuksessa mm. sulfaatista. Katalyyttipinnoite muutti kalvoja vähemmän likaantuviksi, ja näin menetelmän tehokkuus parani. Miselliavusteisella ultrasuodatuksella erotettiin fosforipitoisesta lannoitetehtaan jätevedestä raskasmetalleja selektiivisesti, ja näin mahdollistettiin fosforin uudelleenkäyttö. Kolmannessa tutkimuskohteessa konsentroitiin kalvotislauksen ja käänteisosmoosin yhdistelmällä raskasmetalli- ja typpiyhdisteitä sisältävää synteettistä jätevettä pieneen tilavuuteen. Työssä saavutettiin korkeita raskasmetallien ja suolojen erotustehokkuuksia kaikilla käytetyillä tekniikoilla. Työssä arvioitiin myös yhteenvetona erilaisten hybridimembraanitekniikoiden eroja ja ominaisuuksia ja tekniikoita jaoteltiin menetelmien ominaisuuksien mukaan. Työ antoi uutta tietoa hybridimembraanitekniikoista epäorgaanisten aineiden erotuksessa teollisuuden vesistä.

Ethyl lactate (EL) plays a major role as green solvent and also a replacement for most petrochemical solvents. The esterification process of lactic acid and ethanol to produce EL is an equilibrium-limiting reaction and the selective removal of one of the reaction products can be improved using a membrane reactor and when coupled with a heterogeneous catalyst offers an opportunity for process intensification. This thesis investigates the batch process esterification reaction involving lactic acid (LA) and ethanol (EL) in the presence of a water selective membrane using different cation-exchange resin catalysts. The product was analysed using gas chromatograph coupled with mass spectrometry detector (GC-MS). The analytical methods used for the characterisation of the cation-exchange resins and membrane include Fourier transform infrared coupled with attenuated total reflectance (FTIR-ATR), scanning electron microscopy attached to energy dispersive analyser (SEM/EDAX), Liquid nitrogen physisorption and nuclear magnetic resonance (NMR) respectively. A novel method was developed for carrying out esterification reaction in a gaseous phase system using a flat sheet polymeric membrane. Prior to the esterification reaction, different carrier gases were tested with ceramic membrane to determine the suitable carrier gases for the analysis of esterification product. The four carrier gases used for the permeation test were argon (Ar), helium (He), carbon dioxide (CO2) and nitrogen (N2). A 15nm pore size commercially available tubular ceramic support, consisting of 77%Al2O3 and 23%TiO2 with the porosity of 45% was used for the carrier gas investigation. The support was modified with silica based on the sol-gel dip-coating techniques. The dip-coated membrane exhibited a higher molar flux with He (0.046mol m-2s-1) and Ar (0.037mol m-2s-1) with a much lower flux for N2 (0.037mol m-2s-1) and CO2 (0.035 mol m-2s-1) at 0.30 bar. Helium gas with the highest permeation rate were identified as the suitable carrier gas for the analysis of esterification product with GC-MS. The esterification reaction in the presence of four cation-exchange resins to produce ethyl lactate was carried out between 60-160 oC in a batch and membrane processes to determine the effectiveness resin catalysts for LA esterification. The effect of external mass transfer diffusion limitation between the liquid components and the resin catalysts was avoided by increasing the agitation time of the esterification reaction. The percentage conversion rate of the lactic acid feed from the batch process esterification was found to be in the range of 98.6 to 99.8%. The reaction kinetics of the esterification reaction was described based on two simplified mechanisms of Langmuir Hinshelwood model to describe the adsorption components on the surface of the catalysts. The lactic acid feed gave a conversion rate of up to 100 % confirming the effectiveness of the acetate membrane impregnated resin catalysts in the selective removal of water for the separation of ethyl lactate. The significance of producing ethyl lactate through batch process intensified by a water-selective membrane processes can be recommended for industrial LA production.

Pevaporation is a method for separating volatile components from liquid mixtures at ambient temperatures. The paint processing industry uses Hansen solubility parameters (HSP) to indicate polymer solubility. The potential of this method to predict solvent-polymer affinity was investigated for screening potential membrane materials for the pervaporation of a model solution containing linalool and linalyl acetate (major components of lavender essential oil), in ethanol. Published HSP values were collated for various polymers, and statistically analysed to determine variations in HSP values for polymer species. An investigation of published research into pervaporation of organic/organic binary solutions separated by homogeneous membranes indicated that the solvent whose HSP value was closest to that of the polymer would preferentially permeate. This relationship did not always hold for halogenated solvents or aqueous/organic solutions. Conflicting literature regarding the relationship between solvent uptake by polymers and HSP relative energy differences was resolved using a logarithmic relationship between these two parameters. The following membranes were selected, using their HSP to indicate their potential to interact with lavender oil components: Polyamide (PA: 26.9 micro;m), Polycarbonate (PC: 20.5 micro;m), Poly(ether imide) (PEI: 29.2 micro;m), Poly(ether sulphone) (PES: 27.6 micro;m), Polyethylene (HDPE: 10 micro;m, LDPE: 13-30 micro;m), Polyimide (PI: 30.0 micro;m), Poly(methyl methacrylate) (PMMA: 50 micro;m), Polypropylene (PP: 15.9 micro;m), and Poly(tetrafluoro ethylene) (PTFE: 26.7 micro;m). The HSP (dispersive, polar hydrogen bonding components) for each membrane were calculated using the mean value obtained from swelling experiments, group contribution (calculated using Hoftyzer-Van Krevelen, Hoy and Beerbower methods), refractive indices (dispersive component), dielectric constants (polar component), and published HSP values. Pervaporation experiments investigated the effect of membrane thickness, process temperature, permeate pressure, impinging jet heights, feed flow rates and concentrations, and pre-soaking the membrane; on flow rate and selectivity in a polyethylene membrane. Membrane thickness was the dominant factor in membrane selectivity; the thinnest membranes (11.3-14.8 micro;m) had much poorer selectivity than membranes gt;24.7 micro;m. Temperatures between 22-34ordm;C, permeate pressure lt;10 kPa, impinging jet heights between 0.36-3.36 mm, feed flow rates between 541-1328 mL/min and concentrations between 1.78-6.01 % v/v of linalool and linalyl acetate in ethanol did not significantly affect selectivity. Flow rates increased with operating temperature, permeate pressure, and impinging jet heights. However, feed flow rate and concentration had no effect on membrane flux rate. Pre-soaking the membrane reduced the time to reach steady-state. Selected membranes were further investigated under standard operating conditions (permeate temperature 30ordm;C, permeate pressure lt;10 kPa, impinging jet height 1.36 mm, feed flow rate 804 mL/min and feed concentration of 5% v/v of linalool and linalyl acetate in ethanol). PMMA completely disintegrated in feed solution, and PC was too brittle to make an effective homogeneous membrane. PA, PC, PEI and PTFE had the highest efficiency (selectivity x flow rate) in their homogeneous form. However, PEI, PI and PTFE had the greatest selectivity, thus further trials should be done to improve stability and flow rates through these membranes. Pervaporation selectivity did not always follow trends predicted by HSP. Although polymers such as PA, PEI, PES, and PI preferentially permeated linalool as predicted, PC, PP and PTFE did not preferentially permeate linalyl acetate. This may have been due to the difference in size and diffusivity of these molecules (linalyl acetate, the larger molecule, did not follow the sorption selectivity predictions), or reliability of literature HSP values and those calculated by group contribution. This research shows that HSP is a good screening method for pervaporation membranes, especially where the molecules being separated are of comparable size. Polymers that have HSP close to the desired component and not to other components tend to have the best selectivity and flux characteristics. However, diffusion is an important factor, and is not completely accounted for by HSP. Recommendations for further research include: carrying out pervaporation analyses of selected polymers using pure lavender essential oil; modifying polymers to form asymmetric or composite membranes with improved permeation characteristics; and potential use of thin channel inverse gas chromatography to determine a more accurate HSP which includes diffusivity.

The separation of aqueous and organic mixtures with thermal separation processes is an important and challenging task in the chemical industry. Rising prices for energy, stricter environmental regulations and the increasing demand for high purity chemicals are the main driving forces to find alternative solutions to common separation technologies such as distillation and absorption. These are mostly too energy consumptive and can show limited separation performance, especially when applied to close boiling or azeotropic mixtures. Pervaporation can overcome these thermodynamic limitations and requires less energy because only the separated components need to be evaporated. This separation technology is already well established for the production of anhydrous solvents, but not yet widely distributed in the chemical and petrochemical industry due to some crucial challenges, which are still to overcome. Besides the need of high selective membranes, the development of membrane modules adapted to the specific requirements of organoselective pervaporation needs more research effort. Furthermore, only few modelling and simulation tools are available, which hinders the distribution of this process in industrial scale. In this work, these issues are addressed in a combined approach. In close collaboration with our cooperation partners, a novel membrane module for organophilic pervaporation is developed. A novel technology to manufacture high selective polymeric pervaporation membranes is applied to produce a membrane for an industrially relevant organic-organic separation task. A three step modelling approach ranging from a shortcut and a discrete to a rigorous model is developed and implemented in a user interface. A hydrophilic and an organophilic membrane are characterised for the separation of a 2-butanol/water mixture in a wide range of feed temperature and feed concentration in order to establish a generally valid description of the membrane performances. This approach is implemented in the three developed models to simulate the novel membrane module in industrial scale. The simulations are compared to the results of pilot scale experiments conducted with the novel membrane module. Good agreement between simulated and experimental values is reached.